FIG. 11 shows a conventional display system mounted on a railroad train. In the figure, the reference characters 1 and 2 respectively denote first and second lead cars disposed at both ends of the train and 3 denotes intermediate cars coupled between the lead cars 1 and 2. The lead cars 1 and 2 are equipped with a driver's cab and train driving means, though not shown in the figure. The reference character 4a denotes an image information output means mounted in the first lead car 1; 5a denotes a termination means mounted in the second lead car 2; 6a denotes an image information transmission path which has its one end connected to the image information output means 4a, passes through the intermediate cars 3, and is terminated at its other end by the termination means 5a; 7a denotes branch means provided in the first lead car 1, the intermediate cars 3, and the second lead car 2 to branch the image information transmission path 6a; and 8 denotes image display means provided in the passenger section on each car and connected to the image information transmission path 6a branched by the branch means 7a. 
Its operation is now described. An image signal outputted from the image information output means 4a is distributed to the individual cars 1 to 3 through the image information transmission path 6a. In each car, the branch means 7a extracts the image signal from the image information transmission path 6a and gives it as input to the image display means 8 to cause it to display the image.
The conventional display system carried on the train is constructed as shown above. However, it has the problem that the image signal cannot be distributed to the individual cars when the image information output means carried on the first lead car breaks down. Particularly, when the image information output means breaks down by an accident such as derailment, fire, etc., it cannot provide passengers with evacuation information through image on the display means.
Furthermore, when a train of connected cars is separated during its journey into two trains bound for different destinations, for example, the train in which the image information output means is absent, i.e. the train containing the second lead car, cannot distribute image information.
The present invention has been made to solve the problems shown above, and an object of the invention is to obtain a display system carried on a railroad train which is less likely to get into conditions in which it cannot distribute image information to the cars. Another object is to obtain a display system carried on a train which, even when one train of connected cars is separated into two trains, can distribute image information in both trains of cars.